1. Field of the Invention
This invention relates to waveguide switches and more particularly, to a radio frequency waveguide switch. In still greater particularity, this invention relates to a microwave waveguide switch for selectively diverting energy between one of two output ports.
2. Description of the Prior Art
Waveguide switches are activated by either a DC torque motor or a rotary solenoid. Normally, an actuating device such as either a DC torque motor or a rotary solenoid act through a mechanical linkage to move the waveguide switch.
For example, an actuating device such as a DC torque motor can torque in either rotational direction. But the DC torque motor is usually larger than the rotary solenoid, and this is a problem when space is at a minimum. Also, the DC torque motor is much slower in reaction than the rotary solenoid. Another factor, the DC torque motor is many times more expensive than a rotary solenoid.
The other actuating device is a rotary solenoid. The rotary solenoid can torque in only one direction, but the waveguide switch must be actuated in normally both directions. As a result, the rotary solenoid biases against a spring when it is actuated. If and when the switch returns to the other position, the power to the rotary solenoid is removed and the spring returns the switch to its original position when the solenoid is not actuated. This actuating device has several disadvantages. First, it is relatively slow taking over 500 milliseconds to actuate an E or F band waveguide switch. Secondly, hard mechanical stops at the end of the linkage travel cause the waveguide switch to bounce several times. Normally, a design to remove the bounce will increase the switch travel time even more and cause VSWR problems in the waveguide. Thirdly, the rotary solenoid requires the constant application of power in one of its positions and this takes a large amount of power since it has to hold torque against the spring in this direction.